Is there a compelling reason (supervisor demands it, legacy code) to use trinomial? (it is only a simple explicit FDM, 1st order accurate and conditionally stable).
Why not go the whole way and use Crank Nicolson. And it allows you to calculate the greeks in one sweep.
https://mhittesdorf.wordpress.com/2013/ ... dividends/
I don't see any (e.g. mathematical) reason to use trinomial against a decent FD scheme.
One issue I've noticed: I coded Richardson extrapolation for binomial method but I did not get what I expected. I am rather sceptical of the mathematical applicability of RE for lattice models. You just cannot ignore discontinuous payoffs...
https://kluedo.ub.uni-kl.de/frontdoor/i ... docId/2166